The degree sign.
More from Tech Symbols.
The quickest way is to copy Β° from this page and paste it anywhere. You can also insert it with its Unicode, HTML, or alt code listed above.
Β° is U+00B0 (decimal 176).
Use ° in HTML to render Β° on a web page.
On Windows you can type it with Alt+176 (hold Alt and enter the number on the numeric keypad).
Yes β copying is completely free and unlimited, and works right in your browser with no sign-up.